//这是学习抽象创建的圆类
public class Circle extends Shape{
    private double r;
    final private  static double PI = 3.14;

    public Circle(double r) {
        this.r = r;
    }


    @Override
    public void draw() {
        System.out.println("圆类 r = " + r);
    }

    @Override
    void calArea() {
        System.out.println("圆的面积 = " + PI * r * r);
    }
}
